<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" href="../scripts/plugins/stepper/stepper.css"/>
</head>
<body>
<div class="stepper j_stepper"></div>

<script type="text/javascript" src="../scripts/vendor/jquery-3.4.1/jquery-3.4.1.js"></script>
<script type="text/javascript" src="../scripts/plugins/stepper/stepper.js"></script>
<script type="text/javascript">
    $(function () {
        let options = {value: 1, len: 3, max: 999};
        options.afterChange = function (num) {
            debugger
        };
        $(".j_stepper").stepper(options);
    });
</script>
</body>
</html>